PI 077-14 Lohr am Main, 2014-09-08

Emission reduction drives cooling innovation

With a combination of hydrostatic and electric fan drives the cooling system developed by Rexroth for locomotives delivers accurate engine and inverter cooling regardless of demand.

Energy-saving engine concept with innovative cooling system for diesel-electric locomotives

The railway sector is exhibiting an increasing demand for particularly powerful, environment-friendly and economically efficient technologies. Bosch Rexroth therefore focused leveraging their extensive experience on the development of intelligent cooling systems for diesel-electric locomotives with multi-engine drive systems. This particularly energy-efficient solution for multi-engine locomotives was the result of close cooperation with one of the world’s largest manufacturers of railway vehicles.

Diesel-electric locomotives for the transport of passengers and freight have relied upon one large diesel engine. But since the new EU emission standard Stage IIIB came into effect in 2012, regulations with regard to exhaust emissions have become much stricter. To comply with these new regulations, rail operators’ only choice was to adopt costly exhaust after-treatment methods and more energy-efficient engine controls.

One manufacturer of railway vehicles therefore opted for a new approach: For main-line locomotives, the single “large” diesel engine, was replaced by four smaller engines ”borrowed” from more common use applications. This results in a significant reduction of system costs, including those for exhaust after-treatment. With this innovative solution, the individual diesel engines are cut in or out as needed. The advantage: The fuel consumption and lifecycle costs are reduced by up to ten percent compared to using one large diesel engine.

The cooling system posed a special challenge: Compared to the single-engine solution, a much higher cooling system energy density for the multi-engine concept was required. Moreover, the fan drives must deliver the required cooling capacity based upon actual temperature sensor feedback. The cooling system developed by Bosch Rexroth for diesel engines, generators and inverters employs a combination of hydrostatic and electric fan drives and a customized control package. Following the Rexroth 4EE principles (Rexroth for Energy Efficiency) the cooling system consistently exploits all potential avenues for energy-savings.

The cooling system control package is based on Rexroth solutions for mobile equipment and was configured to suit the requirements of railway technology. The control and sensors monitor the temperature of the engine and generator coolant, charge air and hydraulic oil to determine the necessary cooling power setting. Integrated regulatory functions ensure the fan speed is adjusted to satisfy the demand, thus optimizing energy efficiency and reducing noise levels. Supplemental electric fan systems are used to cool the traction inverter of the drive train.

Bosch Rexroth sees itself as a system partner over the entire lifecycle of railway vehicles. With all solutions, the particular strength lies in the cross-industry approach. Notwithstanding cooling systems for diesel-electric locomotives, Rexroth bundles its comprehensive experience in the field of automotive and industrial applications to provide other innovative systems and components for the railway industry. Very compact, energy-efficient and powerful hydrostatic travel and auxiliary drives complete the portfolio.

Economical, precise, safe, and energy efficient: drive and control technology from Bosch Rexroth moves machines and systems of any size. The company bundles global application experience in the market segments of Mobile Applications, Machinery Applications and Engineering, Factory Automation, and Renewable Energies to develop innovative components as well as tailored system solutions and services. Bosch Rexroth offers its customers hydraulics, electric drives and controls, gear technology, and linear motion and assembly technology all from one source. With locations in over 80 countries, roughly 36,700 associates generated sales revenue of approximately 5.7 billion euros in 2013.

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The Bosch Group is a leading global supplier of technology and services. In 2013, its roughly 281,000 associates generated sales of 46.1 billion euros. (NB: Due to a change in accounting policies, the 2013 figures can only be compared to a limited extent with the 2012 figures). Its operations are divided into four business sectors: Automotive Technology, Industrial Technology, Consumer Goods, and Energy and Building Technology. The Bosch Group comprises Robert Bosch GmbH and its roughly 360 subsidiaries and regional companies in some 50 countries. If its sales and service partners are included, then Bosch is represented in roughly 150 countries. This worldwide development, manufacturing, and sales network is the foundation for further growth. In 2013, the Bosch Group invested some 4.5 billion euros in research and development and applied for some 5,000 patents. This is an average of 20 patents per day. The Bosch Group’s products and services are designed to fascinate, and to improve the quality of life by providing solutions which are both innovative and beneficial. In this way, the company offers technology worldwide that is “Invented for life.”

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Susanne Herzlieb
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